A form of carbon nitride, with a chemical formula of C.sub.3 N.sub.4 and with a structure of beta-Si.sub.3 N.sub.4 has been theoretically formulated and predicted to have a mechanical hardness harder than that of diamond, the hardest material known today (A. Y. Liu and M. L. Cohen, Physical Review, B 41,1027; 1990). An experimental result by Ming Y. Chen et al has partially supported the hardness prediction.
A material with a hardness superior to that of diamond is of a great utility. From production point of view, while the growth temperature of diamond is preferably in the vicinity of 1000 degrees Celsius, the result of Chen et al indicates that this compound can be formed on a substrate held at ambient temperature. This freedom from a high temperature requirement should greatly extend the adaptability of this compound to a larger number of substrate materials.
Based on empirical relations between the mechanical hardness and the optical band gap, this compound should have a wide energy band and a transparency from the ultraviolet to the infrared light. Similar correlation also implies a favorable electrical transport property for electronics applications.
The method to produce this carbon nitride by Chen et al is based on a sputtering on a carbon target with nitrogen ion bombardment. The resultant material, according to their spectroscopic evaluation, consists of only about 50% or less of this component in a matrix of other forms of carbon and nitrogen compounds. These auxiliary materials do not share the superior property of this compound and should be minimized or eliminated, but the method of these authors does not have this provision. One of the objectives of the present invention is to provide a dispersion in the system to separate this compound from other mixed materials while in the deposition. The resultant material becomes 100% pure from this provision.